In the manufacture of an absorbent product, an elastic member is conventionally bonded to a nonwoven fabric with hot melt adhesive or the like. For example, in an absorbent product disclosed in Japanese Patent Application Laid-Open No. 2006-130042 (Document 1), elastic members for legs are bonded to a middle part of an outer covering sheet and inner covering sheet, and hot melt adhesive is applied all over the middle part (containing areas where the elastic members for legs do not exist) in a spiral manner.
On the other hand, in Japanese Patent Publication No. 2664501 (Document 2) and Japanese Patent Publication No. 2954624 (Document 3), a technique is disclosed in which a spiral shaped adhesive is formed by applying adhesive spirally along a left-right direction of a disposable diaper in a short distance and elastic members are bonded to a nonwoven fabric with a plurality of spiral shaped adhesives arranged in a longitudinal direction of the disposable diaper.
In a disposable diaper disclosed in Japanese Utility Model Application Laid-Open No. 61-137607 (Document 4), hot melt adhesive is applied intermittently and linearly in a left-right direction at an adhesion position of elastic member for waist gathers and intermittent straight lines of the hot melt adhesive are arranged in an up-down direction, to form intermittent adhesive parts. In the disposable diaper of Document 4, clearances of the hot melt adhesive in respective intermittent straight lines (i.e., the clearances are distances of spaces where the hot melt adhesive is not applied) become larger toward a waist opening.
Japanese Patent Publication No. 2619595 (Document 5) discloses an apparatus for manufacturing an absorbent product. In a curtain coater thereof for discharging hot melt adhesive in curtain-like form, the hot melt adhesive is intermittently discharged from a plurality of outlets arranged so as to lie across a sheet and therefore the hot melt adhesive is applied only onto positions on the sheet where elastic members are to be bonded.
In the absorbent product of Document 1, since the hot melt adhesive is uniformly applied over a wide area, the amount of hot melt adhesive is large and the manufacturing cost of the absorbent product increases. Also there is a limit to improve the softness of the absorbent product.
On the other hand, in the disposable diapers of Documents 2 to 5, when adhesive is applied, the steps of discharging the adhesive from a nozzle for a short time, stoppage of discharging, and discharging the adhesive for a short time are repeated. Thus, application control of the adhesive is complicated. In addition, since it is difficult to discharge the adhesive stably just after start of discharging, a lump of adhesive falls at a starting end of spiral shaped adhesive and so on, which causes unevenness (i.e., mura) of adhesive.